Finally fixed

src/Disks/AsynchronousReadIndirectBufferFromRemoteFS.cpp

@@ -36,14 +36,10 @@ std::future<IAsynchronousReader::Result> AsynchronousReadIndirectBufferFromRemot
 {
     IAsynchronousReader::Request request;
 
-    impl->set(impl->buffer().begin(), impl->buffer().size());
-    if (impl->initialized())
-    {
-        impl->position() = impl->buffer().end();
-        assert(!impl->hasPendingData());
-    }
-
     auto remote_fd = std::make_shared<ThreadPoolRemoteFSReader::RemoteFSFileDescriptor>();
+
+    /// Resize buffer to 0 and move pos to start.
+    impl->set(impl->buffer().begin(), impl->buffer().size());
     remote_fd->impl = impl;
 
     request.descriptor = std::move(remote_fd);
@@ -76,20 +72,16 @@ bool AsynchronousReadIndirectBufferFromRemoteFS::nextImpl()
     }
     else
     {
-        // if (impl->initialized())
-        // {
-        //     impl->position() = position();
-        //     assert(!impl->hasPendingData());
-        // }
         size = readNext().get();
     }
 
     if (size)
     {
-        //set(working_buffer.begin(), working_buffer.size());
+        size_t offset = pos - working_buffer.begin();
+        assert(offset >= 0);
         swap(*impl);
-        // BufferBase::set(impl->buffer().begin(), impl->buffer().size(), impl->offset());
         impl->absolute_position += working_buffer.size();
+        position() = working_buffer.begin() + offset;
     }
 
     prefetch_future = {};
@@ -142,7 +134,6 @@ off_t AsynchronousReadIndirectBufferFromRemoteFS::seek(off_t offset_, int whence
         prefetch_future = {};
     }
 
-    // impl->seek(impl->absolute_position, SEEK_SET);
     pos = working_buffer.end();
     impl->reset();
 

src/Disks/S3/DiskS3.cpp

@@ -137,18 +137,20 @@ public:
         const String & bucket_,
         DiskS3::Metadata metadata_,
         size_t max_single_read_retries_,
-        size_t buf_size_)
+        size_t buf_size_,
+        bool threadpool_read_ = false)
         : ReadBufferFromRemoteFS(metadata_)
         , client_ptr(std::move(client_ptr_))
         , bucket(bucket_)
         , max_single_read_retries(max_single_read_retries_)
         , buf_size(buf_size_)
+        , threadpool_read(threadpool_read_)
     {
     }
 
     SeekableReadBufferPtr createReadBuffer(const String & path) const override
     {
-        return std::make_unique<ReadBufferFromS3>(client_ptr, bucket, fs::path(metadata.remote_fs_root_path) / path, max_single_read_retries, buf_size);
+        return std::make_unique<ReadBufferFromS3>(client_ptr, bucket, fs::path(metadata.remote_fs_root_path) / path, max_single_read_retries, buf_size, threadpool_read);
     }
 
 private:
@@ -156,6 +158,7 @@ private:
     const String & bucket;
     UInt64 max_single_read_retries;
     size_t buf_size;
+    bool threadpool_read;
 };
 
 DiskS3::DiskS3(
@@ -231,11 +234,13 @@ std::unique_ptr<ReadBufferFromFileBase> DiskS3::readFile(const String & path, co
     LOG_TRACE(log, "Read from file by path: {}. Existing S3 objects: {}",
         backQuote(metadata_path + path), metadata.remote_fs_objects.size());
 
+    bool threadpool_read = read_settings.remote_fs_method == RemoteFSReadMethod::read_threadpool;
+
     auto s3_impl = std::make_unique<ReadIndirectBufferFromS3>(
         settings->client, bucket, metadata,
-        settings->s3_max_single_read_retries, read_settings.remote_fs_buffer_size);
+        settings->s3_max_single_read_retries, read_settings.remote_fs_buffer_size, threadpool_read);
 
-    if (read_settings.remote_fs_method == RemoteFSReadMethod::read_threadpool)
+    if (threadpool_read)
     {
         auto reader = getThreadPoolReader();
         auto buf = std::make_unique<AsynchronousReadIndirectBufferFromRemoteFS>(reader, read_settings.priority, std::move(s3_impl));

src/IO/ReadBufferFromS3.cpp

@@ -31,13 +31,15 @@ namespace ErrorCodes
 
 
 ReadBufferFromS3::ReadBufferFromS3(
-    std::shared_ptr<Aws::S3::S3Client> client_ptr_, const String & bucket_, const String & key_, UInt64 max_single_read_retries_, size_t buffer_size_)
+    std::shared_ptr<Aws::S3::S3Client> client_ptr_, const String & bucket_, const String & key_,
+    UInt64 max_single_read_retries_, size_t buffer_size_, bool use_external_buffer_)
     : SeekableReadBuffer(nullptr, 0)
     , client_ptr(std::move(client_ptr_))
     , bucket(bucket_)
     , key(key_)
     , max_single_read_retries(max_single_read_retries_)
     , buffer_size(buffer_size_)
+    , use_external_buffer(use_external_buffer_)
 {
 }
 
@@ -45,11 +47,18 @@ bool ReadBufferFromS3::nextImpl()
 {
     bool next_result = false;
 
+    /// `impl` has been initialized earlier and now we're at the end of the current portion of data.
     if (impl)
     {
-        /// `impl` has been initialized earlier and now we're at the end of the current portion of data.
-        // impl->position() = position();
+        if (use_external_buffer)
+        {
             impl->set(working_buffer.begin(), working_buffer.size());
+        }
+        else
+        {
+            impl->position() = position();
+        }
+
         assert(!impl->hasPendingData());
     }
     else
@@ -94,6 +103,7 @@ bool ReadBufferFromS3::nextImpl()
         }
     }
 
+    std::cerr << "s3 buffer size: " << impl->buffer().size() << std::endl;
     if (!next_result)
         return false;
 

src/IO/ReadBufferFromS3.h

@@ -43,7 +43,8 @@ public:
         const String & bucket_,
         const String & key_,
         UInt64 max_single_read_retries_,
-        size_t buffer_size_);
+        size_t buffer_size_,
+        bool use_external_buffer = false);
 
     bool nextImpl() override;
 
@@ -52,6 +53,7 @@ public:
 
 private:
     std::unique_ptr<ReadBuffer> initialize();
+    bool use_external_buffer;
 };
 
 }